Energy Efficiency Optimization for Irregular Repetition Slotted ALOHA-Based Massive Access
Zhengchuan Chen, Yifan Feng, Zhong Tian, Yunjian Jia, Min Wang, Tony Q. S. Quek
Abstract
Irregular repetition slotted ALOHA (IRSA) is a promising mechanism to support massive access in Internet of Things (IoT). As IoT devices are usually battery capacity-limited, the energy efficiency (EE) should be paid close attention to when operating the IRSA scheme. This letter improves the EE of devices by adjusting the transmit power and maximum number of packet replicas based on two high-throughput transmission probability distributions of IRSA scheme. Specifically, the optimal transmit power and the optimal packet replica number are found explicitly following individual parameter optimizations. Based on the obtained individual optimums, an iterative algorithm is proposed for finding the global optimum quickly. Numerical results show that the EE of devices can be enhanced significantly by using the found optimums.